Update on diagnosing Malassezia dermatitis in dogs

Is the hunt for this fungal infection hounding you? (Getty Images)You have a skin scraping sample from a itchy dog under the microscope. Hey, you spot one Malassezia organism. Is that enough to make a diagnosis? How many per high power field are significant again?

Throw out the previous guidelines embedded in your synapses and realize that grading Malassezia based on cytologic examination is of no use, says Paul Bloom, DVM, DACVD, owner of the Allergy, Skin and Ear Clinic for Animals in Livonia, Michigan. Indeed, he says the American College of Veterinary Dermatology (ACVD) has officially made this declaration.

"The ACVD has a position statement that states either dogs have Malassezia or they don't," says Bloom. "So when you're evaluating a dog for Malassezia on the skin, if you find any Malassezia at all, it's enough to treat, even if you only find one or two in 10 or 20 oil fields."

Bloom compares it with Demodex species infections in dogs. These mites are a normal part of the fauna on a dog's skins, yet finding any Demodex species on examination of a skin scraping means you better start in on a treatment plan.

Speaking of treating demodicosis, read about the new weapons in your arsenal here. (Hint: It's the isoxazolines you're using for flea and tick prevention.)